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<title>Query Language Terminology - The Java EE 6 Tutorial</title>
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      <td width="400px"><p class="toc level1"><a href="docinfo.html">Document Information</a></p>
<p class="toc level1 tocsp"><a href="gexaf.html">Preface</a></p>
<p class="toc level1 tocsp"><a href="gfirp.html">Part&nbsp;I&nbsp;Introduction</a></p>
<p class="toc level2"><a href="bnaaw.html">1.&nbsp;&nbsp;Overview</a></p>
<p class="toc level2"><a href="gfiud.html">2.&nbsp;&nbsp;Using the Tutorial Examples</a></p>
<p class="toc level1 tocsp"><a href="bnadp.html">Part&nbsp;II&nbsp;The Web Tier</a></p>
<p class="toc level2"><a href="bnadr.html">3.&nbsp;&nbsp;Getting Started with Web Applications</a></p>
<p class="toc level2"><a href="bnaph.html">4.&nbsp;&nbsp;JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="giepx.html">5.&nbsp;&nbsp;Introduction to Facelets</a></p>
<p class="toc level2"><a href="gjddd.html">6.&nbsp;&nbsp;Expression Language</a></p>
<p class="toc level2"><a href="bnaqz.html">7.&nbsp;&nbsp;Using JavaServer Faces Technology in Web Pages</a></p>
<p class="toc level2"><a href="gjcut.html">8.&nbsp;&nbsp;Using Converters, Listeners, and Validators</a></p>
<p class="toc level2"><a href="bnatx.html">9.&nbsp;&nbsp;Developing with JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="gkmaa.html">10.&nbsp;&nbsp;JavaServer Faces Technology Advanced Concepts</a></p>
<p class="toc level2"><a href="bnawo.html">11.&nbsp;&nbsp;Configuring JavaServer Faces Applications</a></p>
<p class="toc level2"><a href="gkiow.html">12.&nbsp;&nbsp;Using Ajax with JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="gkhxa.html">13.&nbsp;&nbsp;Advanced Composite Components</a></p>
<p class="toc level2"><a href="bnavg.html">14.&nbsp;&nbsp;Creating Custom UI Components</a></p>
<p class="toc level2"><a href="bnafd.html">15.&nbsp;&nbsp;Java Servlet Technology</a></p>
<p class="toc level2"><a href="bnaxu.html">16.&nbsp;&nbsp;Internationalizing and Localizing Web Applications</a></p>
<p class="toc level1 tocsp"><a href="bnayk.html">Part&nbsp;III&nbsp;Web Services</a></p>
<p class="toc level2"><a href="gijti.html">17.&nbsp;&nbsp;Introduction to Web Services</a></p>
<p class="toc level2"><a href="bnayl.html">18.&nbsp;&nbsp;Building Web Services with JAX-WS</a></p>
<p class="toc level2"><a href="giepu.html">19.&nbsp;&nbsp;Building RESTful Web Services with JAX-RS</a></p>
<p class="toc level2"><a href="gjjxe.html">20.&nbsp;&nbsp;Advanced JAX-RS Features</a></p>
<p class="toc level2"><a href="gkojl.html">21.&nbsp;&nbsp;Running the Advanced JAX-RS Example Application</a></p>
<p class="toc level1 tocsp"><a href="bnblr.html">Part&nbsp;IV&nbsp;Enterprise Beans</a></p>
<p class="toc level2"><a href="gijsz.html">22.&nbsp;&nbsp;Enterprise Beans</a></p>
<p class="toc level2"><a href="gijre.html">23.&nbsp;&nbsp;Getting Started with Enterprise Beans</a></p>
<p class="toc level2"><a href="gijrb.html">24.&nbsp;&nbsp;Running the Enterprise Bean Examples</a></p>
<p class="toc level2"><a href="bnbpk.html">25.&nbsp;&nbsp;A Message-Driven Bean Example</a></p>
<p class="toc level2"><a href="gkcqz.html">26.&nbsp;&nbsp;Using the Embedded Enterprise Bean Container</a></p>
<p class="toc level2"><a href="gkidz.html">27.&nbsp;&nbsp;Using Asynchronous Method Invocation in Session Beans</a></p>
<p class="toc level1 tocsp"><a href="gjbnr.html">Part&nbsp;V&nbsp;Contexts and Dependency Injection for the Java EE Platform</a></p>
<p class="toc level2"><a href="giwhb.html">28.&nbsp;&nbsp;Introduction to Contexts and Dependency Injection for the Java EE Platform</a></p>
<p class="toc level2"><a href="gjbls.html">29.&nbsp;&nbsp;Running the Basic Contexts and Dependency Injection Examples</a></p>
<p class="toc level2"><a href="gjehi.html">30.&nbsp;&nbsp;Contexts and Dependency Injection for the Java EE Platform: Advanced Topics</a></p>
<p class="toc level2"><a href="gkhre.html">31.&nbsp;&nbsp;Running the Advanced Contexts and Dependency Injection Examples</a></p>
<p class="toc level1 tocsp"><a href="bnbpy.html">Part&nbsp;VI&nbsp;Persistence</a></p>
<p class="toc level2"><a href="bnbpz.html">32.&nbsp;&nbsp;Introduction to the Java Persistence API</a></p>
<p class="toc level2"><a href="gijst.html">33.&nbsp;&nbsp;Running the Persistence Examples</a></p>
<p class="toc level2"><a href="bnbtg.html">34.&nbsp;&nbsp;The Java Persistence Query Language</a></p>
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<p class="toc level3"><a href="">Query Language Terminology</a></p>
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<p class="toc level3"><a href="bnbrg.html">Creating Queries Using the Java Persistence Query Language</a></p>
<p class="toc level4"><a href="bnbrg.html#bnbrh">Named Parameters in Queries</a></p>
<p class="toc level4"><a href="bnbrg.html#bnbri">Positional Parameters in Queries</a></p>
<p class="toc level3 tocsp"><a href="bnbti.html">Simplified Query Language Syntax</a></p>
<p class="toc level4"><a href="bnbti.html#bnbtj">Select Statements</a></p>
<p class="toc level4"><a href="bnbti.html#bnbtk">Update and Delete Statements</a></p>
<p class="toc level3 tocsp"><a href="bnbtl.html">Example Queries</a></p>
<p class="toc level4"><a href="bnbtl.html#bnbtm">Simple Queries</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtn">A Basic Select Query</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbto">Eliminating Duplicate Values</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtp">Using Named Parameters</a></p>
<p class="toc level4 tocsp"><a href="bnbtl.html#bnbtq">Queries That Navigate to Related Entities</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtr">A Simple Query with Relationships</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbts">Navigating to Single-Valued Relationship Fields</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtt">Traversing Relationships with an Input Parameter</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtu">Traversing Multiple Relationships</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtv">Navigating According to Related Fields</a></p>
<p class="toc level4 tocsp"><a href="bnbtl.html#bnbtw">Queries with Other Conditional Expressions</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtx">The <tt>LIKE</tt> Expression</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbty">The <tt>IS NULL</tt> Expression</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbtz">The <tt>IS EMPTY</tt> Expression</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbua">The <tt>BETWEEN</tt> Expression</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbub">Comparison Operators</a></p>
<p class="toc level4 tocsp"><a href="bnbtl.html#bnbuc">Bulk Updates and Deletes</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbud">Update Queries</a></p>
<p class="toc level5"><a href="bnbtl.html#bnbue">Delete Queries</a></p>
<p class="toc level3 tocsp"><a href="bnbuf.html">Full Query Language Syntax</a></p>
<p class="toc level4"><a href="bnbuf.html#bnbug">BNF Symbols</a></p>
<p class="toc level4"><a href="bnbuf.html#bnbui">BNF Grammar of the Java Persistence Query Language</a></p>
<p class="toc level4"><a href="bnbuf.html#bnbuj"><tt>FROM</tt> Clause</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbuk">Identifiers</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbum">Identification Variables</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbun">Range Variable Declarations</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbuo">Collection Member Declarations</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbup">Joins</a></p>
<p class="toc level4 tocsp"><a href="bnbuf.html#bnbuq">Path Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbur">Examples of Path Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbus">Expression Types</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbut">Navigation</a></p>
<p class="toc level4 tocsp"><a href="bnbuf.html#bnbuu"><tt>WHERE</tt> Clause</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbuv">Literals</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbva">Input Parameters</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvb">Conditional Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvc">Operators and Their Precedence</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbve"><tt>BETWEEN</tt> Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvf"><tt>IN</tt> Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvg"><tt>LIKE</tt> Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvi"><tt>NULL</tt> Comparison Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvj">Empty Collection Comparison Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvk">Collection Member Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvl">Subqueries</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvo">Functional Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#gjjnd">Case Expressions</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvr">NULL Values</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvu">Equality Semantics</a></p>
<p class="toc level4 tocsp"><a href="bnbuf.html#bnbvx"><tt>SELECT</tt> Clause</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbvy">Return Types</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbwb">The <tt>DISTINCT</tt> Keyword</a></p>
<p class="toc level5"><a href="bnbuf.html#bnbwc">Constructor Expressions</a></p>
<p class="toc level4 tocsp"><a href="bnbuf.html#bnbwd"><tt>ORDER BY</tt> Clause</a></p>
<p class="toc level4"><a href="bnbuf.html#bnbwe"><tt>GROUP BY</tt> and <tt>HAVING</tt> Clauses</a></p>
<p class="toc level2 tocsp"><a href="gjitv.html">35.&nbsp;&nbsp;Using the Criteria API to Create Queries</a></p>
<p class="toc level2"><a href="gkjiq.html">36.&nbsp;&nbsp;Creating and Using String-Based Criteria Queries</a></p>
<p class="toc level2"><a href="gkjjf.html">37.&nbsp;&nbsp;Controlling Concurrent Access to Entity Data with Locking</a></p>
<p class="toc level2"><a href="gkjia.html">38.&nbsp;&nbsp;Improving the Performance of Java Persistence API Applications By Setting a Second-Level Cache</a></p>
<p class="toc level1 tocsp"><a href="gijrp.html">Part&nbsp;VII&nbsp;Security</a></p>
<p class="toc level2"><a href="bnbwj.html">39.&nbsp;&nbsp;Introduction to Security in the Java EE Platform</a></p>
<p class="toc level2"><a href="bncas.html">40.&nbsp;&nbsp;Getting Started Securing Web Applications</a></p>
<p class="toc level2"><a href="bnbyk.html">41.&nbsp;&nbsp;Getting Started Securing Enterprise Applications</a></p>
<p class="toc level1 tocsp"><a href="gijue.html">Part&nbsp;VIII&nbsp;Java EE Supporting Technologies</a></p>
<p class="toc level2"><a href="gijto.html">42.&nbsp;&nbsp;Introduction to Java EE Supporting Technologies</a></p>
<p class="toc level2"><a href="bncih.html">43.&nbsp;&nbsp;Transactions</a></p>
<p class="toc level2"><a href="bncjh.html">44.&nbsp;&nbsp;Resource Connections</a></p>
<p class="toc level2"><a href="bncdq.html">45.&nbsp;&nbsp;Java Message Service Concepts</a></p>
<p class="toc level2"><a href="bncgv.html">46.&nbsp;&nbsp;Java Message Service Examples</a></p>
<p class="toc level2"><a href="gkahp.html">47.&nbsp;&nbsp;Advanced Bean Validation Concepts and Examples</a></p>
<p class="toc level2"><a href="gkeed.html">48.&nbsp;&nbsp;Using Java EE Interceptors</a></p>
<p class="toc level1 tocsp"><a href="gkgjw.html">Part&nbsp;IX&nbsp;Case Studies</a></p>
<p class="toc level2"><a href="gkaee.html">49.&nbsp;&nbsp;Duke's Tutoring Case Study Example</a></p>
<p class="toc level1 tocsp"><a href="idx-1.html">Index</a></p>
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<a name="bnbth"></a><h2>Query Language Terminology</h2>
<p>The following list defines some of the terms referred to in this
chapter:</p>


<ul><li><p><a name="indexterm-1712"></a><a name="indexterm-1713"></a><b>Abstract schema</b>: The persistent schema abstraction (persistent entities, their state, and their relationships) over which queries operate. The query language translates queries over this persistent schema abstraction into queries that are executed over the database schema to which entities are mapped.</p>

</li>
<li><p><a name="indexterm-1714"></a><b>Abstract schema type</b>: The type to which the persistent property of an entity evaluates in the abstract schema. That is, each persistent field or property in an entity has a corresponding state field of the same type in the abstract schema. The abstract schema type of an entity is derived from the entity class and the metadata information provided by Java language annotations.</p>

</li>
<li><p><b>Backus-Naur Form (BNF)</b>: A notation that describes the syntax of high-level languages. The syntax diagrams in this chapter are in BNF notation.</p>

</li>
<li><p><a name="indexterm-1715"></a><b>Navigation</b>: The traversal of relationships in a query language expression. The navigation operator is a period.</p>

</li>
<li><p><a name="indexterm-1716"></a><b>Path expression</b>: An expression that navigates to a entity&rsquo;s state or relationship field.</p>

</li>
<li><p><a name="indexterm-1717"></a><a name="indexterm-1718"></a><b>State field</b>: A persistent field of an entity.</p>

</li>
<li><p><a name="indexterm-1719"></a><a name="indexterm-1720"></a><b>Relationship field</b>: A persistent relationship field of an entity whose type is the abstract schema type of the related entity.</p>

</li></ul>

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